Project Summary/Abstract Benign lesions of the larynx affect 1 in 40 people at any given time, and treatment traditionally involves surgical excision in the operating room under general anesthesia. It is also possible to treat laryngeal lesions in the clinic, via the endoscopic application of laser energy. This approach is appealing because it can be simply performed in conscious patients with a topical anesthetic, has low complication rates, and has been shown to enable dramatic cost reductions when compared to surgical treatment in the operating room. Despite these bene?ts, of?ce-based procedures are still underutilized because of how challenging they are to perform with available instrumentation. The laser ?bers used in these procedures lack distal articulation, which prevents physicians from treating disease in a number of hard-to-reach anatomical locations within the larynx. We propose to overcome these limitations by creating a new laser probe equipped with a distal articulation mechanism. This probe will be fabricated by combining a thin optical ?ber with a steering sheath that will offer pan and tilt degrees of freedom to amplify a physician's reach during an of?ce-based procedure. The innovation of our device is twofold: (1) We will develop our steering laser probe in an ultra-thin diameter (s 1 mm). This is feasible because the steering sheath will be fabricated using an innovative ?exure-based approach where material is selectively removed from a tube of super-elastic Nitinol to create asymmetric notches. This enables articulation with a single pull-wire, enabling the sheath to be extremely thin. Nearly all other existing steering mechanisms are based on traditional mechanical joints (e.g. pin joints) which are dif?cult to miniaturize and thus not straightforward to use in an endoscopic procedure. (2) We will replace the ?bers in clinical use today (0.4-0.6 mm core diameter) with thinner ones (0.32 mm and below) to enable further miniaturization. Use of ?bers with a 0.4-0.6 mm diameter core is required clinically to produce an adequate laser spot size for treatment. To reproduce the spot sizes produced by these ?bers in thinner-core ?bers, we will utilize an innovative ?ber tapering technique where the geometry of the ?ber tip is engineered to produce prescribed optical light emission characteristics. We will create and validate our steering laser probe via three Speci?c Aims. Aim 1 involves the design, fabrication, and testing of our novel ultra-thin steering sheath. In Aim 2 we will develop a custom optical laser ?ber. Aim 3 addresses the validation of the laser probe prototype in cadaver specimens. The endpoint of this R15 will be proof-of-principle for our ultra-thin steering laser probe, together with a cadaver demonstration of how this instrument would be used in clinical practice.